Sunday, October 24, 2010

Brain Waves

After thinking up that brain alien at the end of my Europa blog, I realized I really have no idea what brain waves are all about. So this is me finding out what I can about them!

The wordnet definition is: “rapid fluxuations of voltage between parts of the cerebral cortex that are detectable with an electroencephalograph”

Holy crap, so many questions need to be answered about that statement.

Ok, first of all. What is the cerebral cortex?

Turns out it’s the biggest part of your brain. It’s all the wrinkly stuff I think about when I think about brains. Actually, it’s a 2mm layer of gray matter that covers the outside of your cerebrum, the walnut-looking part of the brain, shown below.

Peduncle?! Really?
That's the cutest word I have ever heard.

The cortex is made up of neurons and glial cells. Glial is greek for glue, this is the stuff that is sticking it all together and maintaining the structure of the cortex, it’s good stuff but the neurons are the important part for brain waves. They are cells that use electricity to get shit done.

I really like to imagine neurons as little tiny Electros from Spiderman. Try it, it’s way funnier than reality:

All neurons have these basic parts but the shape, size and characteristics will vary depending on what type of neuron it is.

There are three types of neurons

-Sensory neurons: these are the ones that are responsible for basically everything we experience in the physical world. Pain, heat, cold, taste, touch, sound, vision, smell…any way you can physically experience the universe is totally up to the sensory neurons.

The dendrites (little spider leggy things) of the sensory neurons in your tongue, for example, gather information from either chemical interactions (how food is reacting with your taste buds) or physical processes (you bite your tongue and the pressure in the tissue activates the neuron). Neurons take whatever information the world gives them and convert it to an electrical signal that shoots out through the axon and is transmitted to the spinal cord and on to the brain.

Aside: I just found out that the pain signal is transmitted to four different areas of the brain in order to sort this experience and compare it with other experiences. IE: Have I bit my tongue before? Is this time worse?

One of the areas that is put in charge of sorting this stuff out is the limbic system which is the emotional center of the brain. That’s way pain can make us cry!

Anyway, sensory neurons are the reason we can relate to the world outside of our bodies. SO FREAKING COOL. Can you imagine, if a person’s sensory neurons were wired just slightly different from everyone else’s, the entire world might smell like chicken? Or what they interpret as green might be what I see as pink. And who is to say that doesn’t already happen? I could turn this into a real stoner blog about reality and authentic experiences but I think I’ll leave it at that.

However, I will throw in the interesting fact that there are neuroscientists that believe diseases like schizophrenia, a mental disease that makes it difficult to tell the difference between real and unreal experiences, has lots to do with how the sensory nerves are wired. We have no idea what really causes schizophrenia but it’s definitely an interesting theory.

Anyway, long story short: our entire perception of reality is balancing on the electrical activity of our sensory nerves. This deserves it’s own blog. Maybe I’ll get to that someday.

OK…back to the different types of neurons and then hopefully back to brain waves!

Motor neurons transmit impulses from the central nervous system to our muscles and glands. These are the the middle management types underneath the brain who are telling your body to move. The motor pathway is your spine. That’s why spine injuries can paralyze you: motor neurons no longer have a way to communicate with your arms and legs.

Interneurons are pretty much what they sound like. They translate certain information from the sensory neurons to the motor neurons. Sounds like a lame job, but it's an important one. There is so much sensory information constantly bombarding us, the interneurons are the ones that decide what is going to get paid attention to and we are going to act on.

So, from what I gather it goes like this:

1.)Slam your fingers in the door

2.)Sensory neurons tell interneurons about the change in tissue pressure that you are experiencing

3.)Interneurons tell your brain and motor neurons about the sensory neurons’ message. Sometimes the brain can be passed up entirely and motor neurons will fire without permission from the boss. These are called reflexes.

4.)Motor neurons stimulate your muscles to make you physically react to the pain- ie: get your fingers out of the door, scream…ect.

All of the communication that gets done is via electricity, the language of the nervous system.

This four step process goes for every experience, smell, sight….ect, it’s just that pain is the easiest for me to understand because the cause and effect chain seems much more direct. The intricate processes that go along with what your brain tells your body to do based on what you see or hear or smell are way more complicated.

Ok, so now that we know a little about neurons…what do these have to do with brain waves?

Well, as should be obvious, your brain is constantly responding to millions of bits of sensory information. As you are reading these words, sensory neurons are transmitting the light that reaches your eyes into electrical impulses that your brain interprets as written words, the same goes for the feeling of the chair you are sitting on, the smell of the room, the taste of the inside of your mouth, and all the noises around you. With all these neurons firing at different times and places, your brain is FULL of electrical activity constantly.

What’s surprising to me is that some of this electrical activity is periodic. By that I mean, it repeats itself in a predictable pattern. Every certain amount of time there will be a spike in electric potential.

What is electric potential?

Perhaps some of you have seen those gadgets that measure the how good a battery is? They are called voltmeters and are used to determine the electric potential difference between the positive and negative terminals. A greater potential difference between the two terminals means a more charged battery.

What’s happening inside the brain is that there will be a large separation of positive and negative charge caused by brain cells allowing sodium ions to enter their membranes. Since ions have charge, this creates a high potential difference, then suddenly a discharge of ions which lowers the potential difference. This “action potential” gets propagated throughout the brain and happens again and again in several different brain cells.

That’s all I could really find out about the cellular mechanism of action potentials without delving into journals with too much jargon for me to read. If anyone has a better understanding of the action potential and can explain it to me, please do!

Anyway, regardless of exactly why it happens, a graph of this electric potential activity might look something like this:

The y axis is volts (how strong of a battery your brain is) and the x axis is time.

Neuroscientists have classified the different types of brain waves based on how often the spikes occur, this is called the frequency of the waves.

Each unique frequency is associated with a different type of thought process.

Delta waves are the slowest ones, 1 to 4 pulses per second. We emit them when we are deep in dreamless sleep.

Theta waves are of frequencies around 4 to 7 pulses per second and they are associated with reduced consciousness. You might emit theta waves when you are day dreaming. If you are walking around or driving and suddenly realize that you can’t recall the last few minutes…you were probably emitting lots of theta waves. We also emit lots of theta waves when we are doing repetitive tasks.

Alpha waves, which are characterized by frequencies of 7 to 13 pulses per second are associated with mental relaxation. Someone emitting alpha waves is aware of their surroundings but not really concentrating on anything in particular. We probably emit alpha waves while we watch tv.

Beta waves have the highest frequency in the above graph and they are associated with concentration and problem solving.

There are even higher frequency brain waves called gamma waves that come out when a thinker is involved in cross-modal sensory processing. Meaning, they are combining information from two different senses like sight and sound.

When we are sleeping our brain waves sink to lower and lower frequencies; from beta to alpha to theta and finally to delta waves. When we wake up, the process is reversed.

People that hit snooze over and over go through this entire cycle several times every morning. It’s possible for people who do this to stay in the theta state for an extended period. Apparently, this can be a very productive and creative time where the snoozer has a free flow of ideas, memories, and plans. SO THERE, ex’s who got mad at me for hitting snooze 5 times in a row…my brain was doing good things! I definitely have the weirdest dreams during my snooze hour.

Well, this is all fine and good but let's get to the real question, how can we use brain waves in a capitalistic society?

Turns out, there are lots of toys that have to do with brain waves!

I was working as a math tutor for this kid whose parents bought him this thing:

It measures your beta waves. If they strong enough, a fan will be activated under the ball and the ball levitates. This kid had practiced a lot and could levitate the ball. I was really curious about it so I had him try it while I distracted him by clapping and yelling his name right next to him. He couldn’t levitate it while I was doing that. He also couldn’t get it to levitate while he was watching tv. I tried it for a while and couldn’t get it to work. He was telling me I needed to focus on one part of the ball and think about it really hard. Couldn’t do it. Guess I’ll never be a jedi L

I am very suspicious of this. What you would have to be doing in order to change the frequency of your brainwaves is descending from a state of deep concentration to a state of day dreaming. You couldn’t do this by concentrating on making a pitch go up or down because concentration in general is associated with one type of brain wave, beta. Beta waves aren’t going to change depending on what you are concentrating on, just whether or not you are concentrating.

So if he’s really doing what he says he is doing and controlling his brain wave frequency, then when he is pointing down he must be concentrating less and when he’s pointing up he must be concentrating more. But it wouldn’t work if he were concentrating on making the pitch go up and then concentrating on making the pitch go down because in both cases he would be concentrating. Make sense?

Anyway, if he really is doing what he is saying and controlling the synthesizer with his mind, then he is very good at going from concentration to day dreaming just like that.

Either way, if you don’t already love Apples in Stereo you should probably go download their album New Magnetic Wonder and surrender to an hour of pure pop bliss. They are fantastic.

You know who would have a hard time playing with any of those toys? ADHD patients. People with ADHD show a beta wave deficiency. NASA psychologist Alan Pope has actually done research on video games that might treat ADHD. An ADHD kid will have an electroencephalogram (electro-IN-seff-el-o-gram) probe on their head to measure the frequency of their brain waves. The joystick that controls the game will work better if kids can produce higher frequency brain waves, ie: more beta waves. So kids can play their favorite game and learn how to pay attention at the same time.

Pretty cool!

When my electrical engineer dad was in college his senior project involved brain waves. In preparation for this blog, I asked him about it and this is what he said:

Hi Val,

Yes, my senior project at Virginia Tech, back in 1978, was to design an EEG Telemetry device. The unit I designed accepts the output from up to 20 EEG (Electroencephalography) electrodes (typically at ~10 microvolt levels, 0 - 1000 Hz). These signals were amplified by high-gain differential amplifiers, and then used to modulate 20 Intermediate Frequency subcarriers, then placed on a frequency modulated (FM) 100 MHz RF carrier, thus allowing the signal to be transmitted wirelessly on the commercial FM radio band. The purpose of this unit would be for use in emergency situations, for example head injuries, where the EMT's on-scene could attach the probes, and transmit the EEG to a doctor in the hospital, where he could begin his diagnosis before the patient is delivered to the hospital. We had plans to test the operation of this unit on a cat, but did not get that far with the testing.

My design was entirely analog, as that was the only technology readily available at that time (1978). Digital processes / electronics and wireless communication technology have come a long way since then. These days, this type of instrumentation almost always digitizes the signals fairly early in the signal chain. Then there are many more options for channelizing and transmitting the data.

As far as what information about brain activity can actually be derived from brain waves (EEG) -- sorry to say, I am not much of an expert on that, but I'm sure there is lots of info out on the web about that.

Obviously, this thing never got built. But if it did I wonder how useful it would be. I’m not sure how much about a person’s state of being we can really interpret from the waveform of action potentials in their brain besides whether or not they are concentrating.

How freaky would it be if we could tell exactly what someone was thinking by analyzing their brain waves? Sounds like an Asimov story.

Well, there is clearly lots I still don’t know about the mechanisms of the brain.

The brain is intricate and invaluably crucial, definitely the most important organ. But what is it that is telling us that the brain is the most important organ? Oh yeah! The brain! Self preserving propaganda?

Read Tom Robbins, Even Cowgirls Get the Blues for the full philosophical rant on this one.

And while you are at it, if anyone can tell me why cats seem to be the popular animal of choice for brain wave experimentation, I would be interested in knowing!

2 comments:

This has nothing has very little to do with brains, but a lot to do with peduncles:

The portion of the body of a fish that immediatley preceeds the tail fin is called the, "caudal peduncle", which is, consequently, my favorite phrase of all time. Whenever I teach fish anatomy I analogize the caudal peduncle to a "badunkadunk," but call it a "pedunkadunk." I laugh every time and I am always alone in doing so.